My marshall amp project

**Fe 26** · 27 Jul 2006, 04:21 AM

As some of you know, I'm building my own little Marshall amp. It is a head version of the 1974X baby blues breaker. It is 18 watts of tube power.

I am putting this thread in the vets board for one big reason. Tube equipment is deadly.

So;

THIS THREAD IS FOR ENTERTAINMENT ONLY. IN NO WAY DOES IT ENCOURAGE THE READER TO REPEAT ANYTHING THAT THE ORGINAL POSTER HAS DONE. TUBE AMPS CONTAIN DEADLY VOLTAGES. PLEASE TAKE ANY AND ALL VACUUM TUBE EQUIPMENT TO A QUALIFIED TECH FOR ANY AND ALL MAINTANCE.

I chose the 18 watt Marshall kit because of it's ability to do Led Zep, ACDC, and other 60s/70s rock tones and a some what low volume. It's still fucking load, but no where near as bad as say Josh's Orange.

For the kit I decided to go with GDS's 18 watt kit. Unlike many other 18 watt kits, this kit is a pure clone of the original circuit. Most 18 watt kits these days are TMB, meaning they have treble middle and bass controls and no tremolo. One of the nice things about the GDS kit is that it comes with a how to manual and many American made parts. However, this comes at a cost. The GDS kit is probably the most expensive 18 watt kit on the market right now.

Sound samples

http://www.gdsamps.com/mp3.html

I used Christmas money, birthday money, and some ebay money to get the kit. I received around the middle of last semester.

Here are some pics of then

Tools

kit parts

front with tube sockets and pots installed

The inside with just the tube sockets and Out Put Transformer installed

Inside with the heater wires installed

The heater wires are used to send AC current to the vacuum tubes so they can work their magic.

Why are they twisted? The twisting doesn't matter as much as the closeness of the wire. AC current goes back and forth. This can cause hum inside audio equipment. To minimize this, the AC heater wires are kept close together so that the motion of the AC current on each wire can cancel out the effects of the other.

MORE TO COME LATER

**Fe 26** · 27 Jul 2006, 04:53 AM

after test, finals, vacations and trips I finally got back to work on the amp.

july 19th

I first started with the power transformer (its the big thing with brown paper around it)

the tube socket right above the PT is for the rectifier tube. The rectifier tube is used to switch AC current to DC current. Tube amps use both AC and DC current.

To the left of that is the capcan (can sized capacitor). These large capacitors typically house more than one capacitor. They are very dangerous and can kill you in a second.

The multi colored wire goes to the Out Put transformer. It is what powers the speakers. This transformer can out put in 4,8, and 16 ohms. The blue and brown wires go to the power tubes.

At about this time I drew out the entire parts layout in paint bucket. The manual I got was mostly text. I felt a drawing would be easier to fix than the amp in real life.

**Josh** · 27 Jul 2006, 05:14 AM

If this thing sounds sweet you need to build me a low watt OR80 clone.

I'll pay you.

**Fe 26** · 27 Jul 2006, 05:32 AM

I don't know if I'll be able to do that until after I'm out of school and have extra cash to invest in prototyping one.

Making you a low watt OR80 clone isn't as simple as you might think. See, tubes play a big part in how a guitar sounds. You use different tubes depending on how many watts you are using. If I make you a low watt OR80 it will be very unlikely that it will sound just like your original because it will be using different tubes with different character.

Now if I had extra money to try all sorts of different tubes, then maybe we'd get lucky and come up with something that sounds just right. But I won't be getting extra cash for another 2 or even 4 years

an example of what I'm talking about. Have you ever heard about Marshall's orginal amps? They were pure fender bassman (or is it bandmaster?) clones. BUT one day he decided to use a different tube in it, I think the EL84 or EL30something. Anyway, the sound of the amp changed. It became dark and heavy.

**Josh** · 27 Jul 2006, 05:32 AM

Originally Posted by Josh

I'll pay you.

**Tones** · 27 Jul 2006, 11:39 AM

Are you using newly produced tubes? I used to be apart of a home theater forum, and I remember them using tubes from the '50's and '60's within their amps. I assume that the ones of old have a different character than the ones of new.

Sounds like a cool project; it looks like a good way to put your schooling to work.

**Kbu Chan** · 27 Jul 2006, 03:24 PM

Marshall's are the Harley Davidson's of amps.

**Razor Ramon** · 27 Jul 2006, 03:29 PM

I mentioned the building of an amp for me before. I still need to get some money for it but it'll be worth it. Right now I'm using some shitty Ibanez 10-watt amp.